Metal casting has evolved to allow for the casting of more complex workpieces. Some of these casting processes begin with a pattern created in foam or wax. These materials are relatively easy to form in complex shapes. The patterns often are coated with a material to minimize or prevent the mold material, typically sand or clay, from sticking to the completed workpiece or otherwise impacting the surface finish of the workpiece. The pattern is then packed in the mold material and molten metal is poured into the mold. The hot metal melts and displaces the foam or wax pattern so that the workpiece is formed in the shape of the pattern. After cooling to solid form, the workpiece is removed from the mold.
When a cast workpiece is removed from its mold, the workpiece must be cleaned of residue, including sand and clay particles from the mold material, foam or wax residue, and releasing agents and surface finish agents, for example, applied to the wax or foam pattern. The casting is cleaned to provide a clean surface for further processing or to remove reside that could damage the finished assembly of which the casting is a part. The cleaning process can include brushing residue off the exterior, washing with water, and shot blasting with an abrasive material, for example.